Journal: bioRxiv
Article Title: Microglia-derived IL-18 remodels hippocampal plasticity to constrain traumatic fear memory
doi: 10.64898/2026.05.04.721266
Figure Lengend Snippet: a , Schematic of PTSD model establishment. The SPS&S (Single Prolonged Stress & Shock) procedure, consisting of sequential restraint, forced swim, anesthesia, and foot shock. b–c , Contextual fear freezing in SPS&S-exposed and control mice at day 8 ( b ) and day 15 ( c ) post-stress. **P < 0.01, unpaired two-tailed t-test; n = 10 mice per group. d–e , Representative images showing IL-18-GFP fluorescence in sagittal brain sections from IL-18-GFP reporter mice at day 3 post-SPS&S. Images show whole-brain overview with magnified insets of the hippocampus and medial prefrontal cortex (mPFC) ( d ), and basolateral amygdala (BLA). IL-18-GFP specks are represented by green dots generated using IMARIS software. ( e ), scale bars,1mm (overview), 200 μm (inset, hippocampus), 100 μm (inset, mPFC and BLA). f , Quantification of mean IL-18-GFP fluorescent intensity across hippocampus, mPFC, and BLA in control and SPS&S groups. **P < 0.01, ns, not significant; two-way ANOVA with Bonferroni’s post hoc test; n = 3 mice per group. g , Schematic of the IL-18 luciferase reporter assay for quantifying IL-18 bioactivity in dissected brain regions. h , Luciferase activity in hippocampus, mPFC, and BLA from control and SPS&S mice. **P < 0.01, ns, not significant; two-way ANOVA with Bonferroni’s post hoc test; n = 3 per group. i , Schematic of hippocampal tissue collection and processing for IL-18 mRNA quantification by qPCR and protein quantification by ELISA at multiple post-stress time points. n = 3 mice per group. j , Temporal profile of hippocampal IL-18 mRNA levels from 0 to 15 days post-SPS&S. *P < 0.05, **P < 0.01 vs. 0 h; one-way ANOVA with Dunnett’s post hoc test; n = 7-11 per time point. k , Temporal profile of hippocampal mature IL-18 protein levels (normalized to total protein) from 0 to 15 days post-SPS&S. **P < 0.01 vs. 0 h; one-way ANOVA with Dunnett’s post hoc test; n = 7-11 per time point. l , Experimental timeline for intrahippocampal cannula implantation, SPS&S exposure, and daily PBS or IL-18 binding protein (IL-18BP) infusion, with fear memory assessed at days 8 and 15 post-stress. IL-18BP infusion began on day −3 to allow accumulation of antagonist before stress onset, ensuring complete neutralization of stress-induced IL-18. m–n , Contextual fear freezing at day 8 ( m ) and day 15 ( n ) in mice receiving intrahippocampal IL-18BP or PBS following SPS&S. *P < 0.05, **P < 0.01, ***P < 0.001; two-way ANOVA with Bonferroni’s post hoc test; n = 5-9 per group. o , Experimental timeline for intrahippocampal cannula implantation, SPS&S exposure, and daily IL18 infusion, with fear memory assessed at days 8 and 15 post-stress. p–q , Contextual fear freezing at day 8 ( p ) and day 15 (q ) in mice receiving intrahippocampal IL18 or PBS following SPS&S. *P < 0.05, **P < 0.01, ***P < 0.001; two-way ANOVA with Bonferroni’s post hoc test; n = 6–10 per group. Complete statistics are provided in Supplementary Table 1.
Article Snippet: IL-18 binding protein (IL-18BP; MCE) was dissolved in sterile PBS and stored at −80°C.
Techniques: Control, Two Tailed Test, Fluorescence, Generated, Software, Luciferase, Reporter Assay, Activity Assay, Enzyme-linked Immunosorbent Assay, Binding Assay, Neutralization